I like mypy checking in github actions but typically not precommit hooks because of the long runtime. Would be glad to see us move towards typed python though!

Thanks Ken, good point! Do you have any feelings about Mypy alternatives? I was looking at https://mtshiba.github.io/pylyzer/ just now and wondered if that'd be fast enough to run through pre-commit. Generally I like having the checks prior to CI to help with development iterations, but completely agree that Mypy is relatively slow to run (and also sometimes difficult to decipher).

pylyzer looks super exciting! But it's not feature-complete enough to use as mypy alternative with pydantic in the mix. The TypedDict, TypeAlias and Annotated types are pretty important for that. I'd suggest we start with mypy and plan on switching to pylyzer once it's more feature complete.